When a customer requests DSL service (e.g., Asymmetric DSL (ADSL), Symmetric DSL (SDSL), High-speed DSL (HDSL), etc.) it can be difficult for the service provider to determine the highest DSL data rate that the telephone line between the central office and the customer's location can reliably achieve (e.g., with sufficiently low receiver error rates) (i.e., the maximum capable DSL speed). Often, the service provider determines, and offers, a DSL data rate (i.e., a DSL configuration parameter) that is determined based on an estimate of the length of the telephone line. For instance, consider an example customer site that is 12,000 feet from a central office (CO). The service provider knows that most telephone lines of that length can reliably attain 1.5 Million bits per second (Mbps) and, thus, offers that DSL data rate to the customer. However, some customers at that distance can reliably achieve 3 Mbps. Thus, the customer is not offered the highest possible DSL data rate (possibly causing the customer to select a broadband service from an alternative service provider), and/or the service provider loses potential revenue from not being able to sell a higher DSL data rate.
A similar difficulty arises in situations where: a) a customer already has DSL service and now has interest in a higher data rate; or b) a service provider wishes to determine which customers could be offered a higher data rate, in an effort to increase revenues from DSL services. In general, there is a difference between the estimated DSL data rate and the maximum DSL data rate that a telephone line is capable of reliably supporting (i.e., the maximum capable DSL speed).
In typical central offices, a plurality of CO DSL modems (i.e., DSL modems co-located at the CO) are integrated together to form a well-known prior-art DSL Access Multiplexer (DSLAM). Thus, a DSLAM supports simultaneous DSL communications with a plurality of customer premise equipment (CPE) DSL modems (i.e., DSL modems located at a plurality of customer locations) across a plurality of telephone lines.
A pair of CPE and CO DSL modems can measure and report statistics concerning the performance of DSL communications currently active between them (i.e., DSL performance characteristics). For example, the pair of modems can measure the maximum attainable bit rate (MABR) that the pair of modems could currently achieve on the telephone line, a count of receiver errors over fixed intervals of time (e.g., 15 minutes, 24 hours, etc.), etc. Typically, the MABR will be larger than the maximum capable DSL speed that represents the DSL data rate that the telephone line is capable of reliably supporting. A large count of receiver errors in a fixed interval of time can indicate the presence of impulse noise on the telephone line.
DSL performance characteristics (e.g., the current MABR, the count of receiver errors, etc.) can be measured and reported using a variety of well know techniques. For example, they can be measured based on the International Telecommunications Union (ITU) G.992.1 standard for ADSL and/or the ITU G.997.1 standard for management of DSL modems. In particular, DSL modems can monitor forward error correction (FEC) errors to detect and count receiver errors, and can accumulate the number of FEC errors that occurred in a sliding interval of time (e.g., 15 minutes, 24 hours, etc.). However, as discussed above, the current MABR reported by the CO or CPE DSL modem may be different (e.g., higher or lower) from the current DSL data rate being sold to the customer.